Arctic sea ice loss tied to unusual jet stream patterns

Earth has seen some highly unusual weather patterns over the past three years, and three new studies published this year point to Arctic sea loss as a potential important driver of some of these strange weather patterns. The record loss of sea ice the Arctic in recent years may be increasing winter cold surges and snowfall in Europe and North America, says a study by a research team led by Georgia Institute of Technology scientists Jiping Liu and Judith Curry. The paper, titled "Impact of declining Arctic sea ice on winter snowfall", was published on Feb. 27, 2012 in the online early edition of the journal Proceedings of the National Academy of Sciences. "Our study demonstrates that the decrease in Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation, said Judith Curry, chair of the School of Earth and Atmospheric Sciences at Georgia Tech, in a press release. "The circulation changes result in more frequent episodes of atmospheric blocking patterns, which lead to increased cold surges and snow over large parts of the northern continents."

Figure 1. Arctic sea ice in September 2007 reached its lowest extent on record, approximately 40% lower than when satellite records began in 1979. Sea ice loss in 2011 was virtually tied with the ice loss in 2007, despite weather conditions that were not as unusual in the Arctic. Image credit: University of Illinois Cryosphere Today.

Figure 2. The extent of Arctic sea ice loss in the summer July - August - September period in 2007 was about 1.4 million square miles (3.6 million square kilometers) greater than in 1980, according to the University of Illinois Cryosphere Today. For comparison, the lost ice coverage (orange colors) was equal to an area about 44% of the size of the contiguous U.S., or 71% of the non-Russian portion of Europe.

Summertime Arctic sea ice loss: 40% since 1980The Arctic has seen a stunning amount of sea ice loss in recent years, due to melting and unfavorable winds that have pushed large amounts of ice out of the region. Forty percent of the sea ice was missing in September 2007, compared to September of 1980. This is an area equivalent to about 44% of the contiguous U.S., or 71% of the non-Russian portion of Europe. Such a large area of open water is bound to cause significant impacts on weather patterns, due to the huge amount of heat and moisture that escapes from the exposed ocean into the atmosphere over a multi-month period following the summer melt. The Georgia Tech study found that Arctic sea ice loss had caused a 20 - 60% weakening of the west-to-east belt of winds circling the pole in recent years, producing broader meanders in the jet stream that allowed it to get "stuck" in place 20 - 60% more often. When the jet stream gets stuck in place for a long period of time, we say a "blocking pattern" has set up. Since the jet stream marks the boundary between cold, Arctic air to the north, and warmer subtropical air to the south, areas on both sides of the jet are subjected to extended periods of unusually warm or cold weather during a blocking episode. Such a blocking pattern began on January 26, 2012 and lasted until February 11, bringing and exceptionally cold and snowy conditions to much of Europe, which lay on the cold side of an elongated loop of the jet stream that got stuck in place. Conversely, most of North America and northern Siberia saw unusually warm temperatures during this period, since they were on the warm side of the jet stream. Lead author Jiping Liu, a senior research scientist in the School of Earth and Atmospheric Sciences at Georgia Tech, added, "We think the recent snowy winters could be caused by the retreating Arctic ice altering atmospheric circulation patterns by weakening westerly winds, increasing the amplitude of the jet stream and increasing the amount of moisture in the atmosphere. These pattern changes enhance blocking patterns that favor more frequent movement of cold air masses to middle and lower latitudes, leading to increased heavy snowfall in Europe and the Northeast and Midwest regions of the United States." The paper concludes: "if Arctic sea ice continues as anticipated by climate modeling results, we speculate that episodes of the aforementioned circulation change will become more frequent, along with more persistent snowstorms over northern continents during winter."

Figure 3. Waiting for the warm-up after a rare snowfall in Italy during the February, 2012 European cold blast. Image credit: wunderphotographer cathykiro.

Two other studies link Arctic sea ice loss to atmospheric circulation changes"The question is not whether sea ice loss is affecting the large-scale atmospheric circulation...it's how can it not?" That was the take-home message from Dr. Jennifer Francis of Rutgers University, in her talk "Evidence Linking Arctic Amplification to Extreme Weather in Mid-latitudes, presented at December's American Geophysical Union meeting in San Francisco. Dr. Francis presented new research that has just been published in the journal Geophysical Research Letters, which shows that Arctic sea ice loss may significantly affect the upper-level atmospheric circulation, slowing its winds and increasing its tendency to make contorted high-amplitude loops. High-amplitude loops in the upper level wind pattern (and associated jet stream) increases the probability of persistent weather patterns in the Northern Hemisphere, potentially leading to extreme weather due to longer-duration cold spells, snow events, heat waves, flooding events, and drought conditions. Dr. Francis describes her work in a March 5, 2012 post on the Yale environment360 web site.

"Even if the current weather situation may seem to speak against it, the probability of cold winters with much snow in Central Europe rises when the Arctic is covered by less sea ice in summer." That was the opening sentence of a January 26, 2012 press release by a group of European scientists, led by Ralf Jaiser of the Alfred Wegener Institute in Germany. The words proved prescient, because that day marked the beginning of a brutal two-week cold air outbreak over Central and Eastern Europe that killed 823 people and did over $660 million in damage, according to preliminary estimates by insurance broker Aon Benfield. Dr. Jaiser's team, using modeling studies, showed that Arctic sea ice loss weakens upper-level winds over the Arctic in winter, allowing an increased chance of cold air surges over Europe.

Why was the winter of 2011 - 2012 so warm in the U.S.?The winter of 2011 - 2012 in North America was unusually warm--the fourth warmest on record. The cold air spilling out of the Arctic during the winter was confined to Europe, unlike that previous two winters, which were unusually cold and snowy in the Eastern U.S. Obviously, loss of Arctic sea ice is not having the same impact each winter; such factors as El Niño/La Niña, the phase of the 11-year sunspot cycle, and the amount of snow cover in Siberia also have strong influences on the winter weather pattern that sets up. Cold air is less likely to spill out of the Arctic during a solar maximum, as we are now headed towards, so this factor may tend to reduce the odds of getting big cold blasts in the U.S. during the coming two winters. However, cold air may be more likely to spill out of the Arctic in winter due to the decades-long pattern of warming and cooling of Atlantic Ocean waters known as the Atlantic Multidecadal Oscillation (AMO). A 2012 study by NASA scientists found that the warm phase of the AMO (like we have been in since 1995) causes more instances of atmospheric blocking, where the jet stream gets "stuck" in place, leading to long periods of extreme weather. It will be interesting to see how all these factors play out in the coming years. If these three newly-published studies are correct, the U.S. should see more winters like 2010 - 2011 and 2009 - 2010 in coming decades, as Arctic sea ice continues to melt and affect global atmospheric circulation patterns more strongly.

If this year will be anything like 2002, the western and northern Gulf of Mexico coasts will see a lot of action. Six tropical cyclones affected or entered the Gulf of Mexico that year (Bertha, Edouard, Fay, Hanna, Isidore, and Lili). Fortunately they were mostly weak, save Lili, which by comparison to recent storms wasn't all that strong either.

WASHINGTON -- Freak chance was mostly to blame for the record warm March weather that gripped two-thirds of the country, with man-made global warming providing only a tiny assist, a quick federal analysis shows.For much of March, record temperatures hit as high as 35 degrees above normal and averaged about 18 degrees warmer than usual. The United States broke or tied at least 7,733 daily high temperature records in March, which is far more than the number of records broken in last summer's heat wave or in a blistering July 1995 heat wave, according to federal records.The National Oceanic and Atmospheric Administration analyzed the causes and chances of what it nicknamed "meteorological March madness." Meteorologist Martin Hoerling said the main cause was a persistent warm wind sending toasty air north from the Gulf of Mexico. The study is not peer-reviewed and some outside scientists say it is short-sighted.LINK: http://1.usa.gov/HanmNaLINK: http://twitter.com/borenbearsLINK: http://1.usa.gov/H8WhUY"Climate change was certainly a factor, but it was certainly a minor factor," Hoerling said.He said the bigger issue was wind patterns. Low pressure in the Pacific Northwest and high pressure in New England created a perfect funnel, like the gutter lane in a bowling alley, for warm air in the Gulf of Mexico to head north. That air is about 15 to 20 degrees warmer than the air in the Midwest. From time to time that air heads north, but what is unusual is that the wind pattern stayed that way for about two weeks.""Why wouldn't we embrace it as a darn good outcome," Hoerling said. "This was not the wicked wind of the east. This was the good wind of the south."For example, Chicago had nine straight record hot days, eight of them over 80 degrees when usually that city doesn't hit 80 until late June.Hoerling said it's hard at this early point to apportion blame for an event so massive and rare. This seems to be about a once-in-century type event. If this were a once in 40 years type heat wave, as initially predicted, it would be fair to say the chance of it happening is about five part randomness to one part manmade global warming."It is a freak event that appeared to have perhaps a freak ancestor, 1910," Hoerling said. In that year there was a similar heat wave.Hoerling analyzed March temperatures and compared them to past decades and found that since 2001, March has been nearly 2 degrees warmer in much of the country than the 1960-1990 average. So he said that's about 10 percent of the added heat.Hoerling said a lot of people have worried that if March was this hot, what would June be like. But the March weather has little relation to what comes in summer, Hoerling said. "This is not the new reality," he said.Climate scientists said the world should expect more extreme weather - like the March heat wave - as the climate changes. But they also hesitate to attribute single weather events to global warming.Penn State University climate scientist Michael Mann said the longer term view is more important."This winter and spring we're breaking warmth records at more than 10 times the rate we'd expect naturally," Mann said in an email. "So while it is true that individual weather events represent the random rolls of the weather dice, human-caused climate change has loaded those dice. That's why we're seeing 'sixes' come up far more often than we'd expect from chance alone."

Hi Levi. I was one of those bloogers who posted many flood advisories,and news about the flooding that caused some damage to homes and roads in interior PR. Which analogs for the 2012 season you see as a match with this wet pattern that occured in March?

Well it's less about matching up a wet Caribbean during a random spring month than it is about watching how this spring progresses compared to other years that match up in broader ways, such as ENSO. Compared to the analogs that fit the overall climate pattern, this spring is wetter so far, which could be a clue for June and July if it continues.

Quoting Levi32:An interesting note is that the month of March featured above-normal precipitation in the Caribbean, which the island bloggers here have been reporting lately. More interestingly, March had significantly more precipitation than the March's of the main analogs for this upcoming tropical season. This could imply a trend towards a slightly more unstable atmosphere than those years. It is at least more unstable so far than last year (see 2nd figure).

March 2012 Precip Anomalies minus March 2009, 2002, 1957, 1951:

Hi Levi. I was one of those bloogers who posted many flood advisories,and news about the flooding that caused some damage to homes and roads in interior PR. Which analogs for the 2012 season you see as a match with this wet pattern that occured in March?

.SYNOPSIS...LARGE MCS IN RESPONSE TO SMALL CUT-OFF LOW OVER EXTREME SOUTHEASTTEXAS THIS MORNING BEING DRAWN NORTHWARD BY ADVANCING LARGERTROUGH SYSTEM MOVING OUT OF THE ROCKIES TODAY. MCS HAS SPAWNED ARATHER LARGE CURVILINEAR OUTFLOW CONVECTIVE BAND EXTENDING FROMI-20 CORRIDOR NEAR ARKLATEX INTO CENTRAL ACADIANA REGION. NUMEROUSHAIL REPORTS AND HIGH WINDS DUE TO COLD POOL DYNAMICS ALOFT.SOUTHERN EXTENT OF OUFLOW BAND INTERACTING WITH ADVANCING GULFBREEZE BOUNDARY FOR MULTICELLULAR DEVELOPMENT WELL DOWNSTREAM OFADVANCING SQUALL LINE.

Gale Force Winds=================300 NM from the center in northeast quadrant240 NM form the center in southeast quadrant90 NM from the center in southwest quadrant240 NM from the center in northwest quadrant

The next Storm Warning from TCWC Wellington will be issued at 1:30 AM UTC..

This little guy has basically become its own low pressure system. With summer-type heat around, there has been plenty of instability to feed on causing numerous severe thunderstorms across Texas, Louisiana, and Mississippi.

I've seen it happen several times. A front stalls and "backdoors" a little. Because of the movement and orientation of the front, the storms come from the opposite way in which we are accustomed. However, that is very much a summertime pattern. I guess we've really been in a summer-type pattern, so it makes sense.

Quoting Levi32:An interesting note is that the month of March featured above-normal precipitation in the Caribbean, which the island bloggers here have been reporting lately. More interestingly, March had significantly more precipitation than the March's of the main analogs for this upcoming tropical season. This could imply a trend towards a slightly more unstable atmosphere than those years. It is at least more unstable so far than last year (see 2nd figure).

March 2012 Precip Anomalies minus March 2009, 2002, 1957, 1951:

Look at this Levi32! I don't think I've ever seen the MJO stay move in stay this long ever in April as this is typically the driest month of the year.

Quoting Levi32:An interesting note is that the month of March featured above-normal precipitation in the Caribbean, which the island bloggers here have been reporting lately. More interestingly, March had significantly more precipitation than the March's of the main analogs for this upcoming tropical season. This could imply a trend towards a slightly more unstable atmosphere than those years. It is at least more unstable so far than last year (see 2nd figure).

March 2012 Precip Anomalies minus March 2009, 2002, 1957, 1951:

Instability has definitely been a real issue the past 2 seasons. It will be interesting to see if an increase in instability can get us one or two more storms that we wouldn't get in an El Nino year.

Found this on a mississippi weather page..good to know what to do in case i guess..........When a hailstorm strikes •If you are indoors when a storm with large hailstones strikes, stay there. Because large pieces of hail can shatter windows, close your drapes, blinds or window shades to prevent the wind from blowing broken glass inside. Stay away from skylights and doors. •If you are outside, move immediately to a place of shelter.

Funny thing though is that I never speculated one way or the other simply ask a question, but in response to your statement, I could not resist the temptation to test the theory of plagirism. So I revisited his blog and what do you know it is no longer viewable I have been blocked... That allows even more room for further speculation...

Quoting NativeSun:Since we ae entering the first years of a cold PDO and the AMO will begain cooling soon with a very good chance of low solar minimum cycles starting I will make a wild guess that the oceans will cool some what and the ice will return.

Very good chance of low solar minimum??

We are now entering solar maximum. The solar minimum of Solar Cycle 24 ended last year. The next solar minimum isn't for years.

ISOLATED TO SCATTERED AFTERNOON THUNDERSTORMS WILL BE POSSIBLETUESDAY. A FEW OF THESE STORMS MAY BECOME STRONG WITH STRONG GUSTYWINDS...HAIL...AND HEAVY RAINFALL.

AN UPPER LEVEL DISTURBANCE WILL BRING AN INCREASE IN SHOWERS ANDTHUNDERSTORMS ON THURSDAY AND FRIDAY. A FEW STRONG STORMS WILL BEPOSSIBLE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT REQUESTED AT THIS TIME.

FOR ADDITIONAL INFORMATION...VISIT THE NATIONAL WEATHER SERVICEIN JACKSONVILLE WEBSITE ON THE INTERNET AT WEATHER.GOV/JAX.

$$

MKT/JDS/JCH

Yeah, a back door front and an upper disturbance in the gulf should move into FL tomorrow and pop off some thunderstorms over the interior and then are wide Thursday & Friday. Infact we could have a significant hail & wind event here in C & N FL on Friday.

Quoting Levi32:An interesting note is that the month of March featured above-normal precipitation in the Caribbean, which the island bloggers here have been reporting lately. More interestingly, March had significantly more precipitation than the March's of the main analogs for this upcoming tropical season. This could imply a trend towards a slightly more unstable atmosphere than those years. It is at least more unstable so far than last year (see 2nd figure).

March 2012 Precip Anomalies minus March 2009, 2002, 1957, 1951:

Thanks for the post, Levi.

Have you seen the vertical instability in the Gulf of Mexico lately? It's really high.

If you have proof of where he is getting his information from, please present it and rest the case. If not, you have no basis for claiming plagiarism.

Funny thing though is that I never speculated one way or the other simply ask a question, but in response to your statement, I could not resist the temptation to test the theory of plagirism. So I revisited his blog and what do you know it is no longer viewable I have been blocked... That allows even more room for further speculation...

An interesting note is that the month of March featured above-normal precipitation in the Caribbean, which the island bloggers here have been reporting lately. More interestingly, March had significantly more precipitation than the March's of the main analogs for this upcoming tropical season. This could imply a trend towards a slightly more unstable atmosphere than those years. It is at least more unstable so far than last year (see 2nd figure).

What about the storms coming out of the NE across Alabama into Mississippi like they were Saturday night!! I don't think I have ever seen that before!

I've seen it happen several times. A front stalls and "backdoors" a little. Because of the movement and orientation of the front, the storms come from the opposite way in which we are accustomed. However, that is very much a summertime pattern. I guess we've really been in a summer-type pattern, so it makes sense.

A TORNADO WATCH WILL LIKELY BE NEEDED FOR PORTIONS OF NWRN TX...THE ERN OK/TX PANHANDLES...SWRN KS AND WRN OK THIS AFTERNOON AND EVENING.

MID-AFTERNOON MESOANALYSIS SHOWS A COLD FRONT WAS LOCATED FROM SWRN KS INTO ERN NM...WHICH IS BEGINNING TO STALL IN RESPONSE TO PRESSURE FALLS AHEAD OF A POTENT NEGATIVELY TILT MIDLEVEL SHORTWAVE TROUGH. A DRYLINE ACCOMPANIED BY DEEPENING CUMULUS EXTENDED SWD FROM THE KS PORTION OF THE COLD FRONT...WHILE A PACIFIC FRONT WAS BEGINNING TO ENTER W TX. SURFACE TEMPERATURES ALONG THE DRYLINE HAVE WARMED INTO THE MID 80S...AND DEWPOINTS E OF THE BOUNDARY RESIDE IN THE UPR 50S TO MID 60S. THE WARM/MOIST AIRMASS LOCATED ACROSS THE WARM SECTOR COMBINED WITH STEEP MIDLEVEL LAPSE RATES /IN EXCESS OF 8 C PER KM IN THE 700-500 MB LAYER/ ARE CONTRIBUTING TO A VERY UNSTABLE ENVIRONMENT...WITH MLCAPE VALUES NEAR 3000 J/KG.

AS THE UPPER DISTURBANCE LIFTS NWD ACROSS THE SRN HIGH PLAINS THIS AFTERNOON AND EVENING...SHORT-TERM MODEL GUIDANCE INDICATES SURFACE CYCLOGENESIS WILL RAPIDLY TAKE PLACE OVER NERN NM AND THE TX PANHANDLE. STRONG LOW-LEVEL SWLY WINDS OVER W TX...POSSIBLY ACCOMPANYING AN EWD SURGE OF THE PACIFIC FRONT...WILL QUICKLY SPREAD EWD TOWARD THE DRYLINE...RESULTING IN STRENGTHENING LOW-LEVEL CONVERGENCE. AS THIS TAKES PLACE...SCATTERED THUNDERSTORM ARE FORECAST TO DEVELOP FROM THE KS TRIPLE POINT SWD ALONG THE DRYLINE BY 22-00Z.

DURING THE EARLY STAGES OF THIS CONVECTIVE EPISODE TEMPERATURE-DEWPOINT SPREADS WILL BE NEAR 20F OVER THE WARM SECTOR...AND MIDLEVEL FLOW/DEEP LAYER SHEAR WILL BE MARGINAL FOR SUPERCELLS...WHICH MAY NEGATIVELY INFLUENCE THE POTENTIAL FOR TORNADOES DUE TO EXCESSIVE OUTFLOW. HOWEVER...IF STORMS CAN REMAIN QUASI-DISCRETE INTO THE EVENING...THEN A COOLER/MORE HUMID BOUNDARY LAYER COUPLED WITH BACKING/STRENGTHENING 0-1 KM FLOW MAY LEAD TO A MORE SUBSTANTIAL THREAT OF TORNADOES. OTHERWISE...STORMS WILL POSE A THREAT FOR VERY LARGE HAIL GIVEN THE PRESENCE OF LARGE BUOYANCY AND VERY STEEP LAPSE RATES...IN ADDITION TO LOCALLY DAMAGING WIND GUSTS.

Although it has weakened some, this line is still very dangerous an has caused significant damage over portions of Eastern Texas and Louisiana. Trees snapped and homes destroyed are among some of the reports.

A bigger Severe Weather threat will evolve across west-central Texas, western Oklahoma, and central Kansas later on today as storms initiate over the dryline. We could probably make it with a Moderate risk today (for hail), as it appears this will be on organized hail event with likely numerous reports over 2". In addition to the very large hail, tornadoes are also possible.

* SEVERE THUNDERSTORM WARNING FOR... CENTRAL SIMPSON COUNTY IN CENTRAL MISSISSIPPI... THIS INCLUDES THE CITY OF PINOLA... NORTHWESTERN JEFFERSON DAVIS COUNTY IN SOUTH CENTRAL MISSISSIPPI...

* UNTIL 345 PM CDT

* AT 245 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING HALF DOLLAR SIZE HAIL... AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR HEBRON MOVING NORTH AT 15 MPH.

WINDS OF 60 MPH CAN BRING DOWN TREES...POSSIBLY RESULTING IN INJURYAND PROPERTY DAMAGE. ROOFS OF MOBILE HOMES AND OUTBUILDINGS COULD BEDAMAGED...AND MINOR ROOF DAMAGE TO WELL BUILT HOMES AND STRUCTURESCOULD OCCUR.

THE HAIL BEING PRODUCED BY THIS SEVERE THUNDERSTORM WILL LIKELYDAMAGE CARS AND ROOFS. PEOPLE WHO ARE OUT OF DOORS SHOULD MOVE INSIDEA STRUCTURE IMMEDIATELY.

Quoting StormTracker2K:Damm the Euro shows a freeze all the way down to S GA. at days 9 & 10. I highly doubt that based on the pattern so far this Winter and now Spring. Expect to see this change in later runs.